Genetic (AFLP) diversity of nine Cedrela odorata populations in Madre de Dios, southern Peruvian Amazon

Cedrela odorata L., one of the most important neotropical timber species, is threatened by deforestation and unsustainable logging in many parts of its natural range. Information on patterns of genetic variation is useful in informing both reforestation and genetic conservation activities. However, to date, no such information is available in Peru or elsewhere in South America. In the present study, genetic diversity between and within nine Peruvian populations of the species, based on amplified fragment length polymorphism (AFLP) markers, is reported. Overall diversity level was high (Ht = 0.22), as expected for a widespread, long-lived tropical species, and consistent with previous studies carried out in Central America. Levels of intrapopulation diversity were higher than those previously reported for the species (Hs = 0.13-0.21). Analysis of molecular variation revealed genetic differences between two population groups located on different rivers and between populations located on the same rivers. Differences between groups were greater than those within groups. Genetic and geographical distances were significantly correlated. The relatively strong genetic differences between populations may be related to the riparian, essentially one-dimensional spatial distribution pattern of the populations studied. No difference was found in percentage of polymorphic loci between relatively undisturbed and logged populations. The existence of appreciable genetic differentiation over a relatively small part of the species range in the Peruvian Amazon suggests the need for caution in use of seed outside its zone of origin. For genetic conservation purposes, it would probably be prudent to sample (ex situ) or conserve (in situ) populations in each of the major watersheds of the Peruvian Amazon.